/in/foo.c: In function 'main':
/in/foo.c:7:17: warning: 'f' is used uninitialized [-Wuninitialized]
    7 |     c=5.0/9.0*(f-32);
      |               ~~^~~~
/in/foo.c:5:11: note: 'f' was declared here
    5 |     float f,c;
      |           ^